Ron Wolfgang, who is in charge of security for the Alliance for Downtown New York, said, there have been "five times since May 13 where we've observed altercations on the street over the prices being charged for hot dogs, pretzels, water, soda."

Several customers also accused him of short-changing them after overcharging them. One woman pointed out that he had only given her $5 in change when he was supposed to hand her $8; another woman said he didn't even give her change at all.

When a self-identified NBC 4 New York reporter asked the price of a hot dog, Mohammed said $3. When asked why the price changes, he claimed not to speak English -- even though cameras had captured him speaking English earlier, asking customers: "Yes, guys. Yes, sir, you need anything to eat or drink? Have a good day, guys."

Part of the problem is that Mohammed's prices aren't posted, as required by the city's Department of Consumer Affairs. At a hot dog cart around the corner, for example, there's no question how much a hot dog costs -- it's listed at $1.

The Department of Consumer Affairs encourages anyone who is charged more than the posted price -- or encounters a stand with no price listed at all -- to file a complaint at nyc.gov/consumers or to call 311.

In the meantime, the department says it will investigate Mohammed and his practices at the stand.